The present invention relates to the fields of downhole oil, gas and/or geothermal exploration and more particularly to the fields of expandable tools for downhole exploration. There exists in the art a variety of expandable tools used to enlarge the diameter of a wellbore and/or to stabilize a drill string during drilling operations. Expandable tools of this type may contain arms or blades which extend from the sides of a drill string and contact an earthen formation. Examples of these types of expandable tools are described in the following prior art documents.
One such expandable tool is disclosed in U.S. Pat. No. 7,314,099 to Dewey et al., which is herein incorporated by reference for all that it contains. Dewey et al. discloses an expandable downhole tool comprising a tubular body having an axial flowbore extending therethrough, at least one moveable arm, and a selectively actuatable sleeve that prevents or allows the at least one moveable arm to translate between a collapsed position and an expanded position. A method of expanding the downhole tool comprises disposing the downhole tool within the wellbore, biasing the at least one moveable arm to a collapsed position corresponding to an initial diameter of the downhole tool, flowing a fluid through an axial flow bore extending through the downhole tool while preventing the fluid from communicating with a different flowpath of the downhole tool, allowing the fluid to communicate with the different flowpath by introducing an actuator into the wellbore, and causing the at least one moveable arm to translate to an expanded position corresponding to an expanded diameter of the downhole tool.
Another such expandable tool is disclosed in U.S. Pat. App. 2008/0128175 to Radford et al., which is herein incorporated by reference for all that it contains. Radford et al. discloses an expandable reamer apparatus for drilling a subterranean formation including a tubular body, one or more blades, each blade positionally coupled to a sloped track of the tubular body, a push sleeve and a drilling fluid flow path extending through an inner bore of the tubular body for conducting drilling fluid therethrough. Each of the one or more blades includes at least one cutting element configured to remove material from a subterranean formation during reaming. The push sleeve is disposed in the inner bore of the tubular body and coupled to each of the one or more blades so as effect axial movement thereof along the track to an extended position responsive to exposure to a force or pressure of drilling fluid in the flow path of the inner bore.